Because 7,750 engines were not fully assembled in 2009 but in 2010, the Environmental Protection Agency says Navistar should have obtained an exemption in the form of a certificate of compliance, but didn’t.

Proposals for Phase 2 of the federal government’s Greenhouse Gas Emissions regulations are approaching a deadline for publication, but neither the Environmental Protection Agency nor the manufacturers affected know much about what will be in them.

The U.S. Environmental Protection Agency issued a guidance letter late last year to heavy-duty on-highway engine manufacturers outlining how it intends to determine the physical range of adjustment of diesel exhaust fluid quality for certification testing, according to DiscoverDEF.com.